Method of treating fibrous cellulosic materials to impart flame resistance thereto, composition therefor, and products thereof



BSTITUTE .FoR ssme XR Xi? ZQEQQQOS? Patented Apr. l7; IQ

UNITED STAT Joseph W.

dore F.

ES PATENT OFFICE METHOD OF TREATING FIBROUS CELLU- K LOSIC MATERIALS TO IMPART *FLAlVIE RESISTANCE THERETO, COMPOSITION THEREFOR, AND PRODUCTS THEREOF Creely, East Bound'Brook, and Theov 1 7 I Cooke, Martinsviile, N. J.,-assignors to 1 L; I

American Cyanamid Company, New York,:.

N. Y., a corporation of Maine Application February 1"; Serial No. 141,851

18Claims3 (arm-s) Y No Drawing.

I This invention relates to'methods of imparting flame resistance to cellulosic material, more particularly natural or regenerated cellulose or mixtures thereof, and specifically to textiles comprising fibers of such cellulosic materials. The

. invention further relates to the-compositions usedv in such methods and to the flame-resistant cellulosic products thereof.

In the past, various compoundsa nd composi tions have been used or suggested for use as agents for treating fibrous cellulosic materials and other normally flammable organic materials in order to. render them resistant to flame. Agents or treatments for imparting flame-resistance to ordinarily flammable organic materials water-soluble salt of an oxygen-containing acid of phosphorus inwhich phosphorus has a valence of 5, and (4) urea, biuret, ammonium cyanate 01' j ammonium dicyanimide.

In a copending application of one of us, Joseph W. Creely, Serial No. 141,852 filed February 1,: 1950, use of a similar composition in which (1)- may be afinely divide oxide of tin, titanium, anti-' may be classifiedas (1) temporary, (2) semidurable and (3) permanent or durable. This classification is based on the durability of the treatment in providing continued resistance of the treated textile or other material to flame durin use.

The durable treatments heretofore used or suggested have been of three general types: (1) ureaesses for imparting flame-resistance to cellulosic textile materials described in the copending applications of Anne MacMillan Loukomsky, Roy H; Kienle and Theodore R. Cooke, Serial No. 76,644, filed February 15, 1949, now U. S. Patent No. 2,520,103, and Serial No. 64,416, filed December a 9 1948, now U. S. Patent No. 2,519,388. The first of these applications descr-ibesimpregnation of fibrous cellulosic materials with a composition containing specified proportions of (Da finely divided oxide of antimony, (2) a thermally unstable m containing thermoplastic substance, (3) a water-soluble salt of an oxygencontaining acid of phosphorus in which phosphorus has a valencebf5jand (4) either cyanamide dicyandiamide or mixtures thereof, while the latter application discloses a similar use of a composition containing specified proportions of (1) a finely divided oxide of tin, titanium, antimony or bismuth, (2) a thermally unstable halogen-containing thermoplastic substance, (3) a 'vide an additional method for imparting flame- .resistance to cellulosic textile materials which mony bismuth. or mixtures thereof; (2) is the' same, (3)v is a water-soluble, metal-free, nitro- I gen-containing salt of an amino phosphoric acid and (4) is omitted, is described and claimed.

We have now found that by judicious selection of' the particular ingredient falling within class (3) of the above-identified applications of Loukomsky, Kienle and Cooke, the necessity for including a member of class (4) in compositions for imparting name-resistance to cellulosic textiles may be eliminated.

It is an object of the present invention to proavoids the disadvantages of the urea phosphate, double bath precipitation or metallic oxide-chlorinated body types of treatment.

It is another object of the present invention to impart flame-resistance to cellulosic textile:

materials. 1

It is still another object of the present inven-" tion to provide a permanently flame-resistant cellulosic textile material which has an improved hand over that of flame-resistant cellulosic'textile materials given a double bath precipitation treatment or a metallic oxide-chlorinated body type of treatment.

Another object of the present invention is to so treat cellulosic textile materials that they become permanently flame-resistant without excessive tendering.

The above and other objects are attained by;

(B) a water-soluble guanidino or guanylurea salt,

of an oxygen-containing polyacid of phosphorus wherein the phosphorus atom has a valence of 5. The impregnant may be applied to the cellulosicv textile material as a single aqueous liquid compoa v 1, I SEARCH 2,549,059

"has a 2 second after-glow.

compositions, one containing the ingredients of k (A) and the other containing the ingredient (B) V The invention will be described in greater de-.- tail in conjunction with the following specific examples in which proportions are given in parts 7 by weight unless otherwise noted. The examples are merely illustrative, and it is not intended that the scope of the invention be limited to the details therein set forth.

Example 1 312.5 parts of diguanylurea sulfate are reacted in 3257'parts of methyl alcohol-denatured 95% ethyl alcohol with 145 parts of 85% potassium hydroxide. The potassium sulfate which separates out is filtered off and 186 parts of. poly hosphoric acid containing 32-50% meta, 47-60 70 pyro, 3-8% ortho and 82-84% P205 are added to the filtrate. The mixture is stirred thoroughly and allowed to settle after which the excess alcohol'is poured off and the solids dried.

The 32% solution of diguanylurea polyphos phate prepared above (B) is used for padding an 80 x 80 bleached unmercerized cotton fabric. The pH of the bath is about 4.3 and a wet pick-up of about 112% is obtained. The fabric is @r d ie d inrlflmimlieiai g C. in a forcwm c ed for minu es at 160 C. After rinsing and drying a dry add-on of about 8.7 is obtained.

A dispersion of 41 parts of titanium dioxide is prepared by mixing it with 57.7 parts of water and 1.3 parts of the sodium salt of disulfodinaphthylmethane in a homogenizing type of mixer for 10 minutes. The dispersion is then added with stirring to-a mixture of 71.0 parts of polyvinyl chloride latex, 55.5% solids, and 329.0 parts of water.

The cloth which has been treated with the diguanylurea polyphosp'nate isthen padded through the bath containing the titanium dioxide dispersion and the polyvinyl chloride (A) I After one wash a char length of 2% inches is I obtained by the vertical flame test and the cloth has an after-glow of 2 seconds. After 5 washes the char length is 3 inches and the after-glow, 15 seconds. Details of both the washing and flame testing procedures used in this and the following examples are given following Example 4.

Example 2 (A) of Example 1 a wet pick-up of about 114% is' obtained.

After one wash a char length of 3 inches is obtained by the vertical flame test, and the cloth After five washes there is a 5 inch char length and a 28 second after-glow.

" Example 3 A bath (B) is prepared from 131.0 parts of diguanidine carbonate, 132.5 parts of the polyphosphoric acid used in Example 1, 10.0 parts of hexamethylene tetramine and 226.5 parts of water, and 80 x 80 cotton cloth is padded through the bath at 90 C. to a \vet pick-up of about 125%. The fabric is dried for 10 minutes at 85 C. and cured for 16 minutes at 160 C. After rinsing and drying a dry add-on of about 19.5% is ob tained.

A. bath (A) is prepared using 99.5 parts of polyvinyl chloride latex, 55% solids, 71.0 parts of a metallic oxide dispersion prepared as described in Example 1 but using a 41% antimony oxide dispersion in place of the titanium dioxide,

and 329.5 parts of water. The cotton is paddedi in bath (A) to a wet pick-up ofabout and dried, giving a dry add-on of about 15%.

After one wash a char length of 4% inches is obtained. After S-Washes a char length of 4% inches and an after-glow of 11 seconds are obtained. 1

" Example 4 80 parts ofdiguanylurea polyphosphate prepared as set forth in Example 1, 59 parts of water and 25 parts of 28% aqueous ammonia are stirred together and warmed to dissolve.' The solution obtained is added. to a mixture of 50 parts of a dispersion prepared as setforth in Example 1 but using a 41% antimony oxide dispersion in place about is obtained. After drying 10 min.-,

utes at 85 C. and curing 15 minutes at C. a

dry add-0n of about 35% is obtained.

After one wash the char length is 4 inches and the fabric has an after-glow of 5 seconds. After five washes the char length is 3% inches and the.

after-glow i520 seconds.

Similar results are obtained when the titanium dioxide and antimony oxide of the examples are,

replaced by oxidesof tin or bismuth. Mixtures. of two or more o-f the metallic oxides may beused if, desired.

Flame tests on the impregnated cotton fabricsviously regulated to a luminous flame 1 inches. high is placed under the suspended sample so. that the end of the sample extends inch into.. The flame is held under the sample for 12 seconds and then extinguished. The total.

the flame.

length of char in inches. is measured by the tear.

length produced with a tearing weight equal to, approximately 10% of the tearing strength of, the,

unburned fabric.

The washings referred to. in the preceding examples are effected in small oscillating machines; A one pound load is. used for each wash, and the fabrics are washed for 15 minute intervals using 12 liters of 0.5% neutral soap solution at 65-75 C. They are spun and rinsed for from 3-5 minutes in lukewarm water and then spun and.

rinsed further by hand.

The present invention is not limited to the par-.-

ticular polyvinyl chloride of the examples and the thermoplastic substance may be any thermoplastic material containing at least 20%, and

preferably at least 40%, by weight of combined halogen which is capable of rupturing under heat at carbon-halogen bonds. Some examples of such thermoplastic materials arethe polyvinyl bromides, the polyvinylidene chlorides, the poly-.

vinylidene bromides, copolymers of vinyl halides. and vinylidene halides as. for example, of vinyl Samples 2 inches x 10 inches are cut vj;.'.emploved in ma enta:

l chloride. and vinylidene chloride, copolymers. of vinyl halides and acrylic esters as, for example,

of vinyl chloride and methyl, ethyl, propyl, butyl or the like acrylates, halogenated parafims, halogenated diphenyls as pentachlorodiphenyl, pentabromodiphenyl, and the halogenated naphtha- 1 lenes including the chlorinated, brominated, etc.,:

naphthalenes. We prefer to use polyvinyl chloride or a vinyl chloride copolymer containing at, least-80% by weight of combined vinyl "chloride.

Other guanidine or guanylurea salts of oxygen-eicontaining polyacids of phosphorus wherein the.

phosphorus atom has a valence of 5 may be used in place of the salts. of the specific examples. In

general the. salts guanylurea nucleus the.v polyacid.

urea; pyrophosphate, triguanidine tripolyphosphate, triguanylurea tripolyphosphate, tetra-.

guanidinetetrapolyphosphate, tetraguanylurea V tetrapolyphosphate, etc.

will contain a guanidine -or 5V for each phosphorus atom-oi.- Thus, some examples of suitablgsalts are diguanidine pyrophosphate, diguanyl-,-

The phosphorous acid salt used in the-ecome positions of the present invention is extremely critical for only by selection of certain salts is it possible to formulate a three-ingredient com-v position at east as effective as the four-ingredient compositions of the Loukomsky, applications referred to above. In the first place, the phosphorous acid must be a polyacid. Guanidine orthophosphate, for example, is ineffective in a three-ingredient composition and requires the presence of cyanamide, dicyandiamide, urea, biuret, ammonium cyanate or ammonium dicyanimide. Secondly, only the guanidine and guanylurea polyphosphates are effective. Thus, we have observed that other salts of polyacids which are effective in the fouringredient formulations such as, for example, biguanide polyphos- ,phate are not operative in the process and/or compositions of the present invention.

The cel ulosic textile material may be impregnated with the ingredients of the presenfproc'ess V in one or more steps or stages as illustrated by the specific examples. It mav be impregnated with. a dispersion containing all of the necessary in redients within the range of proportions specified below or it may be given a two-bath treatment. If the latter, the textile must be impregnated first with (B), the aqueous solution con-,

taining the guanidine or guanylurea salt of an oxygen-containing polyacid of phosphorus havlng-a valence of 5, and then after drying with (A), the dispersion containing the metallic oxide and the thermally unstable thermoplastic sub-,

stance.

Regardless of the method of impregnation of the fibrous cellulosic textile material it is 'important that the ingredients of (A) and (B) be a wei ht ratio of 1 part of the former 'to from 0.2-8 parts of the latter just as it isv imthose cases where desired up weight based on the dry weight of the untreated I loss of solids during the is relatively unimportant, 75% by weight, based on stantial loss of solids takes place which may be as much as Va of the total weight of the polyphosphate with which the cellulosic material was initially impregnated. In order to obtain a fin- 10%-50%, or in or 75%, by

ished. textile containing from textile, of wash-fast impregnant; the amount of solids in the textile should be sufficiently high to allow for this Weight ing steps.

We .prefen to. employ an aqueous dispersion of:

sion may be varied weight of the dispersion.

Kienle and Cooke The present invention terials of the class consisting of natural celluloses,

regenerated celluloses and mixtures thereof and) including primarily cotton and viscose rayon.

The textile treating compositions of this invenby incorporating therein tion may be modified various modifying agents which aid in further improving the flame-resistant characteristics or the treated cellulosic material or which facilitate the technique of application. For instance, the

compositions may also contain minor (e. 'g., from 1% to 30% by weight of the total solids content) of such glow retardants as the glow-retarding borates, phosphates, pyrophos-' e. g., zinc borate, zinc phosphate, phosphate, stannic phosphate, phenyl diamido phosphate, melamine pyrophosphate, etc. Agents which have a bufiering effect phates, etc.,

"on thecomposition after being applied to the 7-, portant that ingredients (1) and (2) of (A) be range of l35-200 C. and thereafter washing to remove any residual water-soluble substances. The total amount of the ingredients of (A) and (B) with which the cellulosic materialis impregnated is so contro led that the finished flameee ee xti e e ielesi n gent 1%.-.5.Q%

fabric or other textile, e. g'., calcium carbonate,

magnesium oxide, hexamethylene tetramine and.

other polyallrylene polyamines boiling above about 200 C., the amount of said polyamines not exceeding about '7 by weight of ingredient (B) etc., may be incorporated into the treating compositions as desired or as conditions may require.

Bath (B) in a two-bath process should be adjusted to a pH (glass electrode pH) within the range of from about 3 to about 7 if it is not initially within that pH range. Preferably the pH of the aqueous composition containing ingredient (B) is between about a and 6.

The present invention is applicable to the production of a Wide variety of flame-resistant cellulcsic materials, e. g., wearing apparel of all kinds, especially childrens clothes and clothing used by the armed forces, curtains, draperies, sheeting, furniture coverings, linings for electric blankets, net fabrics, non-woven fabrics, chenilles, etc., which are made of cellulosic textile materials.

The terms flame resistance" and flameresistant as used herein and in the appended claims with reference to cellulosic textile materials are used generically to include within their meanings treated cellulosic textile materialswhich, after ignition, will continue to burn at a relatively slow rate as ignition, will burn over only a limited area be-.

as initially impregnated 1 heat treating and wash as desired but they will usually constitute from about 49% to. about 70%. by

applies to cellulosic ma-..-

amounts well as those which, after "fife-resistant will be apparent from the examples herein given that most of the products of our invention proprly fall within the specific classification of fireresistant cellulosic textile materials.

The terms textile and textile materia as used generically herein and in the appended claims include within their meanings filaments, fibers, rovings, slivers, threads, yarns,

yarns, etc., as such or in woven, felted or other wise formed fabrics, sheets, cloths and thelilre. L f

We claim: 1. A method of imparting flame-resistance to a celluloslc textile material of the class consisting of natural celluloses, regenerated celluloses and mixtures thereof, which comprises impregnating said material with an association of an aqueous liquid'composition containin ingredients comprising (1) a finely divided oi gde of a metal of the group consisting of antimon bis uth, tin and (2) a thermoplastic substance co by weight of combined hal r titanium and taining at least gen and capable hon-halogen bonds, the ingredients of (l) and (2) which together are designated hereinafter as,

twisted cellulosic textile materials. It"

of rupturing under heat at carauaow of (A) and (1B) being'employed in'a weight ratio of 1 part of the former to from 0.243 parts of the. latter; heating the impregnated textile at a temperature within the range of about 135-200 C.; and washing the resulting textile to remove any residual water-soluble substances therefrom,

the total amount of the ingredients of (A) and I (B) with which the textile initially is impregj nated being such that the finished flame-resistant textile contains from 75% by weight, based on the dry weight of the about 10% to about untreated textile, of wash-fast impregnant.

7.-A method as in claim 6 wherein ingredient (2); is a vinyl chloride polymerization product.

6 wherein ingredient 8. A method as in claim (B) i diguanidine pyrophosphate.

9. A method as in claim 6 wherein ingredient (B) is diguanylurea pyrophosphate.

10. A method as in claim ceeding about '7 by weight of the ingredient (B), of a polyalkylene polyamine having a, boiling point substantially-above 200 C. u

11. A method of imparting flame-resistance to a textile comprising fibers of a cellulosic material of the class consisting of natural celluloses,

regenerated celluloses and mixtures thereof ent (B) having a pH of from about 3 to about 7,; v

heating the impregnated material at a temperature within the range of about 135-200 C.; and washing the resulting material to remove any re-. sidual water-soluble substances therefrom, the total amount of the ingredients of (A) and (B) with which the cellulosic textile material initially is impregnated being such that the finished flame-resistant textile contains from about 10% to about 75% by weight, based on the dry weight of the untreated textile, of wash-fast impregnant.

2. A method as in claim 1 wherein the cellulosic textile material is cotton.

3. A method as in claim 1 wherein the cellulosic textile material is viscose rayon.

rial of the class consisting of natural celluloses, -';-f;regenerated celluloses and mixtures which comprises impregnating said textile with J. an aqueous dispersion having a pH within the "-range of 3-7 and comprising thereof (1) a finely divided oxideof a metal of the group consisting of antimony, bismuth, tin and titanium, (2) a thermoplastic substance containing at least 20% by weight or combined halogen and capable of rupturing under heat at carbon-halogen bonds, the ingredients of (1) and (2) which together are designated hereinafter as (A) being employed in a weight ratio of 1 part of the former to from 0.6-20 parts of the latter, and (B) a compound selected from the group consisting of the guanidine and guanylurea salts of an oxygen-containing polyacid of ph sphorus wherein the phosstances therefrom;

phorus atom has a valence of 5, the ingredients which comprises impregnating said textile with an aqueous solution having a pH within the range of 3- 7 and containing (B) a compound selected from the group consisting of the guanidine and guanylurea salts of an oxygen-containing polyacid of phosphorus wherein the phosphorus atom has a valence of 5; heating the impregnated textile at a temperature within the range of -'200 C.; washing the resulting textile to remove any residual Water-soluble subimpregnating the heated and washed textile with ingredients comprisingv (1) a finely divided oxide of a metal selected from the group consisting of antimony, bismuth, tin and titanium and (2) a thermoplastic substance containing at least 20% by weight of combined halogen and capable of rupturing under heat at carbon-halogen bonds, the ingredients of (1) and (2) which together are designated hereinafter as (A) being employed in a weight ratio of 1 part of the former to from 0.6-20 parts of the latter, the ingredients of (A) and (B) being employed in a weight ratio of 1 part of the former to from 0.2-8 parts of the latter; and heating the impregnated material at a range of about 135 C. to 200 C., the total amount of the ingredients of (A) and (B) with which the said textile is impregnated being such that the finished flame-resistant textile contains from about 10% to about 75% by weight, based on the dry weight of the untreated textile, of wash fast impregnant.

12. A method as in claim 11 wherein the textile is cotton.

13. A method as in claim 11 wherein ingredient (B) is diguanidine pyrophosphate.

14. A method as in claim 11 wherein ingredient (B) is diguanylurea pyrophosphate.

15. A flame-resistant cellulosic textile mate- I 18. An aqueous dispersiiid having a pH of 6 wherein theaque-- ous dispersion contains a small amount, not ex-v temperature within the accepts I 9 from about 3-7 and comprising (1) a finely divided oxide of a metal selected from the group consisting of antimony, bismuth, tin and titaformer-to froxn'0.6-20 parts of the latter and being dispersed in water containing (B) a compound selected from the group consisting of the guanidine and guanylurea salts of an oxygencontaining polyacid of phosphorus wherein the phosphorus atom has a valence of 5, the inva-n nevi-Q gradients of (A) and (B) being employed in a' a weight ratio of], part of the former to from 0.2-8 parts of thelatter.

JOSEPH W. CREELY. THEODORE F. COOKE.

REFERENCES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 2,413,163 Bacon Dec. 24, 1946 15 2,482,756 Ford et a1. Sept. 27, 1949 5 w VC u n. 

1. A METHOD OF IMPARTMENT FLAME-RESISTANCE TO A CELLULOSE TEXTILE MATERIAL OF THE CLASS CONSISTING OF NATURAL CELLULOSES, REGENERATED CELLULOSES AND MIXTURES THEREOF, WHICH COMPRISES IMPREGNATING SAID MATERIAL WITH AN ASSOCIATION OF AN AQUEOUS LIQUID COMPOSITION CONTAINING INGREDIENTS COMPRISING (1) A FINELY DIVIDED OXIDE OF A METAL OF THE GROUP CONSISTING OF ANTIMONY, BISMUTH, TIN AND TITANIUM AND (2) A THERMOPLASTIC SUBSTANCE CONTAINING AT LEAST 20% BY WEIGHT OF COMBINED HALOGEN AND CAPABLE OF RUPTURING UNDER HEAT AT CARBON-HALOGEN BONDS, THE INGREDIENTS OF (1) AND (2) WHICH TOGETHER ARE DESIGNATED HEREINAFTER AS (A) BEING EMPLOYED IN A WEIGHT RATIO OF 1 PART OF THE FORMER TO FROM 0.6-20 PARTS OF THELATTER, AND OF AN AQUEOUS LIQUID COMPOSITION CONTAINING AN INGREDIENT COMPRISING (B) A COMPOUND SELECTED FROM THE GROUP CONSISTING OF THE GUANIDINE AND GUANYLUREA SALTS OF AN OXYGEN-CONTAINING POLYACID OF PHOSPHORUS WHEREIN THE PHOSPHORUS ATOM HAS A VALENCE OF 5, THE INGREDENTS OF (A) AND (B) BEING EMPLOYED IN A WEIGHT RATIO OF 1 PART OF THE FORMER TO FROM 0.2-8 PARTS OF THE LATTER, THE AQUEOUS COMPOSITION CONTAINING THE INGREDIENT (B) HAVING A PH OF FROM ABOUT 3 TO ABOUT 7; HEATING THE IMPREGNATED MATERIAL AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 135*-200* C.; AND WASHING THE RESULTING MATERIAL TO REMOVE ANY RE-, SIDUAL WATER-SOLUBLE SUBSTANCES THEREFROM, THE TOTAL AMOUNT OF THE INGREDIENTS OF (A) AND (B) WITH WHICH THE CELLULOSE TEXTILE MATERIAL INITIALLY IS IMPREGNATED BEING SUCH THAT THE FINISHED FLAME-RESISTANT TEXTILE CONTAINS FROM ABOUT 10% TO ABOUT 75% BY WEIGHT, BASED ON THE DRY WEIGHT OF THE UNTREATED TEXTILE, OF WASH-FAST IMPREGNANT. 